Buggy code:
public class ConfigurationImpl implements Externalizable , Configuration , ValueListener { private static final String SEP = System . getProperty ( "line.separator" ) ; private static final Localizer _loc = Localizer . forPackage ( ConfigurationImpl . class ) ; public ObjectValue logFactoryPlugin ; private boolean _readOnly = false ; private Map _props = null ; private boolean _defaults = false ; private final List _vals = new ArrayList ( ) ; private PropertyChangeSupport _changeSupport = null ; private PropertyDescriptor [ ] _pds = null ; private MethodDescriptor [ ] _mds = null ; private Set _prefixes = new HashSet ( ) ; public ConfigurationImpl ( ) { } public ConfigurationImpl ( boolean loadDefaults ) { } public boolean loadDefaults ( ) { ConfigurationProvider provider = Configurations . loadDefaults ( getClass ( ) . getClassLoader ( ) ) ; if ( provider != null ) provider . setInto ( this ) ; try { fromProperties ( new HashMap ( System . getProperties ( ) ) ) ; } catch ( SecurityException se ) { } _defaults = true ; if ( provider == null ) { Log log = getConfigurationLog ( ) ; if ( log . isTraceEnabled ( ) ) <START_BUG> log . trace ( ConfigurationImpl . _loc . get ( "no-providers" ) ) ; <END_BUG> return false ; } return true ; } public String getProductName ( ) { } public LogFactory getLogFactory ( ) { } public void setLogFactory ( LogFactory logFactory ) { } public String getLog ( ) { } public void setLog ( String log ) { } public Log getLog ( String category ) { } public Log getConfigurationLog ( ) { } public Log getManagementLog ( ) { } public Log getProfilingLog ( ) { } public Value [ ] getValues ( ) { } public Value getValue ( String property ) { } public void setReadOnly ( boolean readOnly ) { } public void instantiateAll ( ) { } public boolean isReadOnly ( ) { } public void addPropertyChangeListener ( PropertyChangeListener listener ) { } public void removePropertyChangeListener ( PropertyChangeListener listener ) { } public void valueChanged ( Value val ) { } public void close ( ) { } public BeanInfo [ ] getAdditionalBeanInfo ( ) { } public BeanDescriptor getBeanDescriptor ( ) { } public int getDefaultEventIndex ( ) { } public int getDefaultPropertyIndex ( ) { } public EventSetDescriptor [ ] getEventSetDescriptors ( ) { } public Image getIcon ( int kind ) { } public synchronized MethodDescriptor [ ] getMethodDescriptors ( ) { } public synchronized PropertyDescriptor [ ] getPropertyDescriptors ( ) { } private PropertyDescriptor getPropertyDescriptor ( Value val ) throws IntrospectionException { } private String findLocalized ( String key , boolean fatal , Class scope ) { } public Map toProperties ( boolean storeDefaults ) { } public void fromProperties ( Map map ) { } private void removeFoundProperty ( Value val , Map remaining ) { } private Object [ ] lookUpProperty ( String property , Map map ) { } private void warnInvalidProperty ( String propName ) { } private Collection newPropertyList ( ) { } protected boolean isInvalidProperty ( String propName ) { } public void setProperties ( String resourceName ) throws IOException { } public void setPropertiesFile ( File file ) throws IOException { } public void assertNotReadOnly ( ) { } public boolean equals ( Object other ) { } public int hashCode ( ) { } static String toXMLName ( String propName ) { } public void readExternal ( ObjectInput in ) throws IOException , ClassNotFoundException { } public void writeExternal ( ObjectOutput out ) throws IOException { } public Object clone ( ) { } public boolean removeValue ( Value val ) { } public Value addValue ( Value val ) { } public void addPropertyPrefix ( String prefix ) { } public StringValue addString ( String property ) { } public FileValue addFile ( String property ) { } public IntValue addInt ( String property ) { } public DoubleValue addDouble ( String property ) { } public BooleanValue addBoolean ( String property ) { } public StringListValue addStringList ( String property ) { } public ObjectValue addObject ( String property ) { } public PluginValue addPlugin ( String property , boolean singleton ) { } public PluginListValue addPluginList ( String property ) { } }

Fix:
log . trace ( ConfigurationImpl . _loc . get ( "no-default-providers" ) ) ;